1. Field of the Invention
The invention relates to a method of using a laser-based position measuring device to determine the flatness of a foundation to which a structure, machinery or equipment is to be mounted. In particular, the invention relates to any situation where a building structure, machinery or equipment needs to be mounted in a level manner, such as a machine on a factory floor, particularly that of a newly built factory, a building on its foundation, a wind powered electrical generator on a mounting slab, etc. Thus, for purposes of this application, the term foundation should be viewed in its general sense as an underlying base or support, or a body or ground upon which something is built up or overlaid.
2. Description of Related Art
When installing machinery in a factory, especially in a newly built factory, before mounting of the machinery in place, e.g., by drilling holes to bolt down the feet of the machinery to the floor, it is necessary to know how much each foot will be higher or lower than a certain reference point since most factory floors are not perfectly level.
Position measuring devices are available in many types. One well-known type is known under the generic term “total station.” A total station is combination of an electronic theodolite or transit and an electronic distance measuring (EDM) device with associated computer based software. Angles and distances from the instrument to points to be surveyed are measured, and the coordinates of the actual positions of the points are calculated.
Most total station instruments measure angles by electro-optical scanning of extremely precise digital bar-codes etched on rotating glass cylinders or discs within the instrument. Distance measurement is often accomplished with a modulated microwave or infrared carrier signal that is generated by a small solid-state emitter within the instrument's optical path and reflected from the object to be measured. The modulation pattern in the returning signal is read and interpreted by a computer associated with the total station. The speed-of-light lag between the outbound and return signal is translated into distance. Most total stations use a purpose-built glass prism as the reflector for the EDM signal and can measure distances out to a few kilometers. The reflector is typically held by a person at various positions in the survey while an operator operates the device. However, it is also possible to have robotically operated devices in which the operator can remotely control the machine, while holding the reflector. These devices are quite complex and are very expensive.
There is a need for a simpler, and thus less expensive alternative to mere trial and error adjustments during installation of factory floor mounted machinery.